package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author YJY
 * @since 2025-03-16
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IUserService userService;

    @Resource
    private IFollowService followService;
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog-> {
            this.queryBlogUser(blog);
            //3.查询blog是否被点赞了
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result queryblogById(Long id) {
        //1.查询博客
        Blog byId = getById(id);
        //2.查询博客有关的用户
        queryBlogUser(byId);
        //3.查询blog是否被点赞了
        isBlogLiked(byId);
        return Result.ok(byId);
    }

    private void isBlogLiked(Blog blog) {
        //1.获取登录用户
        UserDTO user = UserHolder.getUser();
        if(user == null) {
            // 用户未登录 无需查询是否点赞
            return;
        }
        Long userId = user.getId();
        //2.判断当前登录用户是否已经点赞
        String key = RedisConstants.BLOG_LIKED_KEY+blog.getId();
        Double member = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(member!=null);

    }

    @Override
    public Result likeBlog(Long id) {
        //1.获取登录用户
        UserDTO user = UserHolder.getUser();
        Long userId = user.getId();
        //2.判断当前登录用户是否已经点赞
        String key = RedisConstants.BLOG_LIKED_KEY+id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if(score == null) {
            //3.如果未点赞,可以点赞
            //3.1.数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            //3.2.保存用户到Redis的set集合
            if(isSuccess) {
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else{
            //4.如果已点赞,取消点赞
            //4.1.数据库点赞-1
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            //4.2 把用户从Redis的set集合移除
            if(isSuccess) {
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    public void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = RedisConstants.BLOG_LIKED_KEY + id;
        // 1. 查询前 5 的点赞用户（按分数降序，即最新点赞）
        Set<String> top5 = stringRedisTemplate.opsForZSet().reverseRange(key, 0, 4);
        if (top5 == null || top5.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }

        // 2. 解析用户 ID
        List<Long> ids = top5.stream()
                .map(Long::valueOf)
                .collect(Collectors.toList());

        // 3. 按 ID 顺序查询用户（确保结果与点赞顺序一致）
        String idStr = StrUtil.join(",", ids);
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids) // ✅ 正确参数
                .last("ORDER BY FIELD(id,"+idStr+")") // ✅ 预编译防注入 //顺序 保证
                .list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

        return Result.ok(userDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
        // 1.获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 2.保存探店笔记
        boolean save = save(blog);
        if(!save) {
            return Result.fail("新增笔记失败!");
        }
        // 3.查询笔记作者的所有粉丝 select * from tb_follow where follow_user_id = ?
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();

        // 4.推送笔记id的所有粉丝
        for (Follow follow : follows) {
            //4.1 获取粉丝id
            Long userId = follow.getUserId();
            //4.2 推送
            String key = FEED_KEY+userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());

        }


        // 5.返回id
        return Result.ok(blog.getId());
    }


    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2.查询收件箱 滚动分页查询 ZREVRANGEBYSCORE key Max Min  LIMIT offset count
        String key = FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        //3.非空判断
        if(typedTuples == null || typedTuples.isEmpty()) {
            return Result.ok();
        }
        //4.解析数据: blogId,score(时间戳),offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;//最后一个元素一定是最小时间
        int os = 1;
        for(ZSetOperations.TypedTuple<String>tuple:typedTuples) {
            //4.1 获取id
            String idStr = tuple.getValue();
            ids.add(Long.valueOf(idStr));
            //4.2 获取分数(时间戳)
            long time = tuple.getScore().longValue();
            if(time == minTime) {
                os++;
            }else{
                minTime = time;
                os = 1;
            }

        }

        //4.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();

        for (Blog blog : blogs) {
            queryBlogUser(blog);
            isBlogLiked(blog);
        }
        //5.封装并返回
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setOffset(os);
        scrollResult.setMinTime(minTime);
        return Result.ok(scrollResult);
    }
}
